Recovery of erectile function after radical prostatectomy is quantitatively related to the response to intraoperative cavernous nerve stimulation.

OBJECTIVE

To correlate the results of intraoperative cavernous nerve stimulation (CaNS) at radical prostatectomy (RP), with preoperative erectile function (EF) and to determine the significance of the results of stimulation after RP in predicting the recovery of EF.

PATIENTS AND METHODS

The study included 183 potent men who had not received neoadjuvant therapy, and who had RP without nerve grafting, with intraoperative CaNS, between July 1998 and April 2002. Follow-up International Index of Erectile Function (IIEF) questionnaires were returned at a median (range) of 25 (1-51) months. Age, preoperative EF, neurovascular bundle (NVB) status, pathological stage and CaNS results were evaluated as independent predictors of the recovery of EF, as assessed by the IIEF, using Cox proportional hazards analysis.

RESULTS

CaNS strength before RP correlated with the level of preoperative potency (P = 0.023). CaNS strength after RP correlated with that before RP (P < 0.001) and the degree of NVB preservation (P = 0.007). Only age and maximum percentage change in penile girth after RP were significant independent predictors of the recovery of EF. For each 1-year increase in age, men were 4%, 6% and 5% less likely to achieve erections, defined as an IIEF EF domain score of >or=17, >or=22 and >or=26, respectively. For each 1% increase in maximum percentage change in penile girth after RP with CaNS, men were 26% (95% confidence interval 7-48%), 22% (0-49%), and 47% (17-83%) more likely to achieve erections, with an IIEF EF score of >or=17, >or=22 and >or=26, respectively. There was a significant false-negative rate, with 15% of patients with a minimal CaNS response normalizing their EF score and 35% recovering scores of >or/=22.

CONCLUSIONS

While CaNS results after RP correlated strongly with the degree of NVB preservation, the degree of penile girth change, rather than degree of surgeon-documented NVB preservation, was independently predictive of the recovery of EF.